The reality is, when I was a kid, my grandfolks and folks started to think about getting rid of vehicles around 100,000 miles. The standard these days is 200,000. It's been a very big jump in quality since I was young.
Most folks drive about 15,000 miles a year, with lots of variability, so a vehicle really should be operating well with minimal maintenance and fluid changes and minor stuff, for close to 13 years for most of us.
People tire of driving the same vehicle long before the vehicle won't give decent service, anymore.
We have a 16 year old, a 15 year old, a 12 year old, and the "baby" is now 8. The only non-owner-caused unplanned maintenance on any of them has been minor other than rebuilding the steering on the Dodge truck, and that's a well-known problem. (As is blowing the head gasket on the Cummins with over 32 lbs of boost, but like I said, owner-induced doesn't count here for this post! LOL...)
I suspect the next one to need major maintenance will be the GMC (the 12 year old), it'll need a transmission. It will have made it to the 12-13 year expected lifespan but well under 200,000 miles when it finally trashes the tranny. Another well-known problem.
Interestingly, there's so many folks who won't save up money to buy and MUST use long term financing that the deals are right at 10 years when most lenders stop lending. The prices fall like rocks thrown off a high cliff at that point, and it doesn't really seem to matter much the mileage or the condition of the vehicles. Cash handed to a private seller who just feels like buying something newer who's taken good care (with records) of something at the 10 year mark, feels like stealing it if its significantly lower than 150,000 miles at that age. They can't sell it to someone who's going to finance it, but they know they'll get hosed on a trade in... they'll be lucky to get auction value... so they sell privately. Finding a 10 year old with good maintenance and 100,000 miles isn't too hard. And you'll pay 1/3 of the new price or lower.
Eventually I'll get the bug to buy a new diesel truck and some folks will get some nice deals on all these old vehicles, but not this year. Play money plus more went to flying this year, which for this crowd -- is as it should be!